This invention relates to a method for the manufacture of a non-coagulative organosilicone resin which retains heparin by virtue of a covalent bond.
Artificial internal organs, extracorporeal circulation devices and other medical accessories such as catheters, blood preservers and injectors are today medical necessities and among these are many made of various synthetic resins such as silicone rubber, polyvinyl chloride, Teflon, polyethylene, polyurethane, polycarbonate, polyethylene terephthalate, polyvinyl alcohols, etc. Being foreign matter, these resins often cause undesirable reactions in living organisms such as, for example, coagulation of blood.
Organosilicone resins exhibit less adverse effects on living tissues and induce less blood coagulation than the resins enumerated above and, therefore, are extensively used as raw materials for medical utensile. Nevertheless, the non-coagulative property of these resins is by no means perfect. For this reason, it is an important task to improve the non-coagulative property of organosilicone resins.
As a means for enhancing the non-coagulative property of the resins, there has heretofore been suggested a method directed to incorporating into the resin an anticoagulating agent represented by heparin. This method is referred to as "heparinization." Heparinization is applicable to organosilicone resins and is believed to be effective in improving these resins in terms of non-coagulative property. If the heparin thus incorporated into the resin is retained therein by virtue of ionic bonds, however, the effect brought about by the presence of heparin will gradually diminish because the heparin in that state readily exudes from the resin. It follows as a consequence that the anticoagulating activity exhibited by this agent cannot be retained for a long time.
The primary object of the present invention is to provide a method for the manufacture of a non-coagulative organosilicone resin which retains the anticoagulant, heparin, fast and stably for a long time.